What ever happens, just keep being calm, reasonable and doing what is ever necessary to continue your relationship with your son.
Keep positive, keep nice, keep kind, if she pushes, don't push back, and don't push, keep making suggestions, eventually it will all win through, but every time a negative is added from which ever side ,that delay you all being on the same team again, which is team support our lovely son.
Time passes fast, children grow, it changes,
twenty plus years ago, I was in exactly the opposite position, DS's father moved to London, and it took a lot of work for us to get back to being all on the same team, we did get there.
Honestly, let any resentment go, it really will help, really focus on all the positives, the negatives will fade,
It will very apparent in your voice when you have, and that will in time evoke a very different response, you are both in a vicious circle.
I think you will end up having many a happy day surfing our lovely south west beaches, walking the coastal path, and moors, it a brilliant playground, you just have to get through the hard first years.